• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.560-565
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• 2004

Bacteriocin producing lactic acid bacteria (LAB) were isolated from Kimchi by using spot-on-the-lawn method. Listeria monocytogenes, Staphylococcus aureus, and Lactobacillus plantarum were used as indicators. One isolate (P3-l) produced a bacteriocin efficiently inhibiting the growth of Listeria monocytogenes. 16S rDNA sequence and sugar utilization test identified that P3-1 was a Lactobacillus sakei strain. Accordingly, the isolate was named as Lactobacillus sakei P3-1. L. sakei P3-1 produced a bacteriocin which efficiently inhibited the growth of Listeria monocytogenes but did not inhibit other Gram positive and negative organisms tested. The bacteriocin was stable against heat, organic solvent, and pH variation and it retained 50% of activity after 10 min heat treatment at 10$0^{\circ}C$. The molecular weight of Sakacin P3-1 was estimated to be 4 kDa by SDS-PAGE.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.175-181
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• 2011

Kimchi is a group of traditional fermented vegetable foods in Korea and known to be the product of a natural mixed-fermentation process carried out principally by lactic acid bacteria (LAB). According to microbial results based on conventional identification, Leuconostoc mesenteroides and Lactobacillus plantarum were considered to be responsible for the good taste and over-ripening of kimchi, respectively. However, with the application of phylogenetic identification, based on 16S ribosomal RNA gene similarities, a variety of Leuconostoc and Lactobacillus species not detected in the previous studies have been isolated, together with a species in the genus Weissella. Additionally, Lactobacillus sakei has been accepted as the most populous LAB in over-ripened kimchi. In this study, Leuconostoc and Weissella species inhibiting the growth of Lb. sakei were isolated from kimchi for future applications to do with kimchi fermentation. From 25 kimchi samples, 378 strains in the genera Leuconostoc and Weissella were isolated and 68 strains identified as Lc. mesenteroides, Lc. citreum, Lc. lactis, W. cibaria, W. confusa, and W. paramesenteroides exhibited growth inhibition against Lb. sakei. Most of the strains also had antagonistic activities against Lb. brevis, Lb. curvatus, Lb. paraplantarum, Lb. pentosus, and Lb. plantarum. Their antagonistic activities against Lb. sakei were more remarkable at lower temperatures of incubation.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.316-322
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• 2011

Lactobacillus sakei OPK2-59 isolated from kimchi was found to have ${\gamma}$-aminobutyric acid (GABA) producing ability and glutamate decarboxylase (GAD) activity. When the Lactobacillus sakei OPK2-59 was cultured in MRS broth with 59.13 mM and 177.40 mM monosodium glutamate (MSG), the optimum temperature range and pH for growth were $25-37^{\circ}C$ and pH 6.5, respectively. GABA conversion rates in MRS broth with 59.13 mM and 177.40 mM MSG were 99.58% and 31.00%, respectively at $25^{\circ}C$ and 48 h of cultivation. By using the cell free extract of Lactobacillus sakei OPK2-59, MSG was converted to GABA and the conversion rate was 78.51% at $30^{\circ}C$, pH 5. Conversion of MSG to GABA was enhanced by adding salts such as $CaCl_2$, $FeCl_3$, $MgCl_2$. These data suggest that the ability of Lactobacillus sakei OPK2-59 to produce GABA results from the activity of GAD in the cells and GABA conversion by the cell extract containing GAD can be enhanced by $CaCl_2$, $FeCl_3$, $MgCl_2$.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.313-316
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• 2011

We isolated and identified a novel probiotic strain, Lactobacillus sakei proBio65 from Kimchi. To determine whether L. sakei proBio65 has an immunomodulatory effect, we investigated cells via an in vitro screening system which co-cultured freshly isolated mesenteric lymphocyte with probiotics. A significant increase of $Foxp3^+$ transcription regulatory factor expression was observed, followed by an increase in anti-inflammatory cytokines transcription regulatory factor. L. sakei proBio65 exhibited high levels of the IL-10/IL-12 production ratio and enhanced Foxp3 expression in vitro. L. sakei proBio65 may thus be therapeutically useful for the modulation of inflammatory immune disorders.

• Journal of fish pathology
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• v.16 no.2
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• pp.119-123
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• 2003

We have selected an valuable pmbiotic strain; Lactobacillus sakei BK19 which has wide antagonic spectrum against fish pathogens . Present study investigated cultural characterization of L. sakei BK19 including pH tolerance , susceptibility of antibacterial agents and growth pattern with different environment such as nutritions, temperature and salinity. L. sakei BK19 showed Significantly higher resistance at low pH(around pH 4) environment and relative high antibiotic tolerance . In the study of optimal culture condition, maltose and saccharose provided the optimal nutritional culture condition while lactose and mannitol were unable to supply its carbon source for the fermentation of L. sakei BK19. Moreover. L. sakei BK19 showed good growth at the temperature range of 15 to $45^{o}C$ und the NaCl concentration of 0 to 7%. Hence, this particular probiotic strain may be benificial both in seawater and fresh weter conditions.

• KSBB Journal
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• v.28 no.1
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• pp.18-23
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• 2013

The purpose of this work was to investigate the several functional characteristics of Lactobacillus sakei JK-17 isolated from long-term fermented kimchi, Muk Eun Ji. Initially, phylogenetic analysis using 16S rRNA sequencing was performed to identify the isolate JK-17, and the strain could be assigned to Lactobacillus sakei and designated as L. sakei JK-17. The strain was registered in GenBank as [JX841311]. The changes of bacterial growth and residual organic acids were monitored and HPLC was used to measure quantitatively two organic acids, lactic acid and acetic acid, produced in the culture during 84 hours of incubation. During the incubation period, several functional characteristics of L. sakei JK-17 were examined. L. sakei JK-17 culture depleted nitrite concentration 94.75%. Antioxidant activity of cultural supernatants of L. sakei JK-17 was approx. 53.8%, and ${\beta}$-galactosidase activities were 0.243 units/mL at pH 7.0 and 0.387 units/mL at pH 4.1, respectively. The antibacterial activities against food-poisoning causing bacteria were examined with 20-fold concentrated culture supernatants from L. sakei JK-17 and the antibacterial effects were clearly observed against all bacteria tested in this work.

• Journal of Life Science
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• v.24 no.1
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• pp.46-53
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• 2014

Lactobacillus sakei 383, which showed the highest GABA content in fermented soycurd, survived in artificial gastric fluid (pH 3.0) up to 3 h, and the survival rate was 88%. L. sakei 383 was tolerant to bile juice during incubation in MRS broth with 0.3% oxgall, and the survival rate was 99%. The survival ratio of L. sakei 383 was high in media containing less than 6% NaCl. L. sakei 383 produced an antibacterial substance against various pathogens, including Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Salmonella typhi. The quality characteristics of soycurd fermented with L. sakei 383 were measured during the fermentation period. The viable cell number reached a peak ($10^{11}CFU/ml$) 36 h after fermentation and then slowly decreased. According to the fermentation time of L. sakei 383, the acidity of soycurd increased and the pH decreased until 12 h, and they were maintained thereafter. The moisture, crude ash, crude protein, crude fat, and crude fiber content was 94.88, 0.22, 2.38, 1.16, and 0.03%, respectively. The content of total and reducing sugar was comparatively higher in the soycurd fermented with L. sakei 383 than in nonfermented soycurd. The essential and nonessential amino acid content was 11.2 and 38.65 mg/100 g.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.201-207
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• 2016

The aim of this study was to investigate the potential of lactic acid bacteria (LAB) strains as probiotics. Two strains were isolated from healthy chicken cecum and their acid and bile tolerance, residual organic acids, antibacterial activity against pathogenic bacteria, and immunomodulation activity were measured. Identification of the isolated strains was performed using the API 50CHL system and phylogenetic analysis using 16S rDNA sequencing. The isolates were determined to be Lactobacillus sakei strains. The acid tolerance of strains L2 and L8 was high enough that 75% of the inoculum survived in pH 2 for 2 h. The bile tolerance of both strains was observed at a 1% Oxgall concentration in MRS broth. The production of organic acids (lactic acid and acetic acid) and pH changes during growth were monitored and the maximum concentrations were obtained after 48 h of incubation. Culture supernatants of the two LAB strains showed strong antibacterial activity against pathogenic bacteria. The heat-killed LAB cells also induced high levels of immune cell proliferation compared with the control, and stimulated IL-6 and TNF-α production in mouse macrophages. Therefore, L. sakei strains L2 and L8 can be considered suitable probiotic bacteria.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.390-396
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• 2011

Lactobacillus sakei is known to be the most populous lactic acid bacteria in over-ripened kimchi. Twenty three strains of Leuconostoc species inhibiting the growth of Lb. sakei were isolated from kimchi and amongst these the Leuconostoc mesenteroides strain CK0122 exhibited the highest antagonistic activity against Lb. sakei. The culture supernatant of the strain CK0122 was fractionated by a molecular weight cutter and lyophilized. The fraction with a molecular weight of less than 3,000 Da showed antagonistic activity against Lb. sakei. The antibacterial activity of the active fraction was sensitive to proteinase K treatment, confirming its proteinaceous nature (bacteriocin). The crude bacteriocin was active in the pH range of 4 to 7 and extremely stable after 15 min of heat treatment at $121^{\circ}C$. The crude bacteriocin inhibited the growth of Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Alcaligenes xylosoxydans, Flavobacterium sp., and Salmonella typhimurium.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.71-78
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• 2020

Lactobacillus sakei S1 strongly inhibits the expression of interleukin (IL)-6 and IL-1β in lipopolysaccharide-induced peritoneal macrophages by a mechanism for which lactic acid bacteria from kimchi that inhibit tumor necrosis factor-alpha (TNF-α) were isolated. Therefore, we further evaluated the protective effect of this strain on the colitis mouse model induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS significantly elevated myeloperoxidase (MPO) expression, macroscopic scores, and colon shortening. Oral L. sakei S1 administration resulted in reduction of TNBS-induced loss in body weight, colon shortening, MPO activity, expression of cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB). L. sakei S1 inhibited the expression of inflammatory cytokines IL-1β, IL-6 and TNF-α, induced by TNBS, but enhanced IL-10 expression. L. sakei S1 showed resistance to artificial digestive juices and adherence to intestinal epithelial Caco-2 cells. Thus, L. sakei S1 may inhibit the NF-κB pathway and be used in functional food to treat colitis.